JPH10146577A - Treating agent for heavy metal-containing waste and stabilizing treating method of heavy metal-containing waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent secondary environmental pollution by continuing stabilizing effects while elution of a heavy metal ion can be stabilized to a standard value or under by a method wherein a treating agent for a heavy metal-containing waste containing a pozzolanic active substance which is solid at ordinary temperature, is used. SOLUTION: A pozzolanic substance is a substance which is cured by reacting with water and calcium oxide, calcium hydroxide or aluminum hydroxide, etc. For those pozzolanic substances, that in which a silica constituent content when the silica constituent in pozzolanic active substance is converted to SiO2 is 40wt.% or over, preferably 50wt.% or over, or an alumina constituent content when the alumina constituent in the pozzolanic active substance is converted to Al2 O3 is 0.2wt.% or over to and excluding 40wt.%, is preferably used. A blended amount of the pozzolanic active substance when heavy metal-containing waste is treated for stabilization with the pozzolanic active substance is generally 0.1-60 pts.wt. to 100 pts.wt. of the heavy metal-containing waste, preferably 1-40 pts.wt. and further preferably 5-20 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste treatment agent effective for insolubilizing and stabilizing heavy metals contained in general waste and industrial waste, and a method for treating the same. More specifically, it is effective for insolubilizing heavy metals contained in incineration ash and fly ash generated from incinerators and melting furnaces for municipal garbage, industrial waste, sludge, etc., and for stabilization. The present invention relates to a waste treatment agent and a method for treating the same.

[0002]

2. Description of the Related Art In recent years, as wastes generated from cities and factories have increased, wastes containing heavy metals have been required to be sufficiently detoxified for environmental measures. In particular, municipal waste incinerated ash and industrial waste containing heavy metals are subject to strict regulations when treating and disposing of them as specially managed waste.

Conventionally, when disposing of waste containing heavy metals, a method of mixing with cement, adding water as necessary, and kneading the mixture to prevent elution of heavy metals and the like has been adopted. However, the standard value for elution of heavy metals from landfill waste that has been applied since 1995 has been determined to be the most difficult to stabilize in the case of lead. ) Is required to stabilize to 0.3 mg / l or less, but it is difficult to clear this standard with cement alone.

[0004] In the case of mixing and solidifying waste, which is a typical cement such as ordinary Portland cement, the calcium hydroxide generated during the hydration process promotes the hardening of the cement, but excessively. The generated calcium hydroxide increases the pH of the mixture of waste and cement, and increases the solubility of heavy metal compounds such as lead, which is an amphoteric metal. It is thought to be damaged.

[0005] In addition, when cement is used, it is good to use it continuously, but when processing is interrupted due to maintenance, etc., it remains unless the equipment such as cement silo, piping, mixer and kneader is washed. There is also a problem such as maintenance workability that the treated material is solidified on the wall of the machine.

Further, attempts have been made to capture and stabilize heavy metal ions by chemical treatment with a sulfur-containing chelating agent or the like, but according to this, it is possible to stabilize to below the elution reference value. . However, such a drug is not only expensive, but also has insufficient retention of heavy metal ions after the stabilization treatment. There is a problem that the elution amount of heavy metal ions increases.

[0007]

As described above, it is not only difficult to stabilize heavy metal ions below the elution standard, but also to stabilize the conventional heavy metal-containing waste treating agent and treatment method. However, there is a problem in the retention and durability of the retention, and there is a concern about secondary pollution over time.

[0008] An object of the present invention is to stabilize heavy metal-containing waste to stabilize elution of heavy metal ions below a reference value, and to maintain the effect of stabilizing heavy metal ions to completely prevent secondary pollution. It is an object of the present invention to provide a treating agent and a treating method capable of preventing the occurrence of

[0009]

Means for Solving the Problems In view of such circumstances, the present inventors have intensively studied for a treating agent and a treating method that can completely stabilize heavy metal-containing waste, and as a result, have completed the present invention. . That is, the present invention

(1) A heavy metal-containing waste treating agent characterized by containing a pozzolanic active substance which is solid at ordinary temperature, (2) a silica component contained in the pozzolanic active substance when the silica component is converted into SiO ₂ (3) The treating agent according to (1), wherein the amount of the alumina component in the pozzolanic active substance is 0.2% by weight or more and 40% by weight in terms of Al ₂ O _3. The treatment agent according to the above (1), wherein the average particle size of the pozzolanic active substance is less than 30.
The treatment agent according to any one of the above (1) to (3), wherein the specific surface area of the pozzolan active substance is 5,
(6) The treatment agent according to any one of the above (1) to (4), wherein the treatment agent is 000 to 3,000,000 cm ² / g
Furthermore, the treating agent according to any one of the above (1) to (5), further comprising a dispersant and water; (7) the above-mentioned (1) further comprising one or more sulfur-containing compounds and / or water-soluble phosphates. )
To (6), (8) the treating agent according to (7), wherein the sulfur-containing compound is a thiourea derivative and / or a carbamic acid derivative, and (9) a water-soluble phosphate. The treatment agent according to the above (7), which contains one or more of lime superphosphate and / or sodium tripolyphosphate, (10) a waste containing heavy metals, and the treatment according to any one of the above (1) to (9). A method for treating heavy metal-containing waste, characterized by adding, mixing and kneading by adding an agent and, if necessary, water.
1) A heavy metal-containing waste, the treatment agent according to any one of the above (1) to (9), and if necessary, water, and the mixture is mixed, kneaded, and then heated to 40 ° C. or more. (12) Heavy metal-containing waste shall be incinerated ash and fly ash from garbage incineration plants, contaminated soil, or metals that must satisfy the criteria set forth in Prime Ministerial Ordinance No. 5 (13) The method for treating a heavy metal-containing waste according to the above (10) or (11), which is an industrial waste containing (13) a heavy metal having a neutral or acidic pH in an eluate after an elution test based on Announcement 13 The treatment method according to any one of the above (10) to (12), wherein the treatment waste and the basic substance according to any one of the above (1) to (9) are added to the contained waste for treatment. (14) The pH of the eluate after the elution test based on (1) above, in that heavy metal-containing waste
(10) The treatment method according to any one of (10) to (12), wherein the treatment agent and the acidic substance according to any one of (9) are added and treated. 14) A processed product obtained by the processing method described in any one of the above.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The pozzolanic active substance used as an essential component in the present invention is a substance which cures by reacting water with calcium oxide, calcium hydroxide, aluminum hydroxide or the like, and is not particularly limited as long as it has the above properties. Specific examples of the pozzolan-activating substance that can be used include silica dust, diatomaceous earth, talc, aerosil, white carbon, kaolin, metakaolin, activated clay, and acid clay.
These pozzolanic active substances have a silica component content of 40% by weight or more, preferably 50% by weight or more when the silica component in the pozzolanic active substance is converted into SiO ₂ , or an alumina component in the pozzolanic active substance. To Al ₂ O ₃
It is preferable to use one having a converted alumina component content of 0.2% by weight or more and less than 40% by weight. These pozzolanic active substances can be used alone or in combination of two or more.

A pozzolanic active substance that is amorphous has higher reactivity and a higher stabilizing effect on heavy metals.
Further, the pozzolanic active substance having a finer and larger specific surface area has a higher reactivity and a higher adsorptivity, and thus has a higher stabilizing effect on heavy metals. The average particle size is usually 30 μm
Or less, preferably 20 μm or less, particularly preferably 5 nm
10 μm, and the specific surface area is usually 5,000 to
3,000,000 cm ² / g, preferably 10,000
0 to 3,000,000 cm ² / g, particularly preferably 3
It is from 3,000 to 3,000,000 cm ² / g.

When stabilizing heavy metal-containing waste with a pozzolanic active substance, the amount of the pozzolanic active substance to be compounded depends on the type of pozzolanic active substance used and the type and amount of heavy metal contained in the heavy metal-containing waste, particularly lead. Although it depends on the content of 0.1 to 0.1 parts by weight of heavy metal-containing waste,
６０60 parts by weight, preferably 1-40 parts by weight, more preferably 1.5-20 parts by weight.

Although the heavy metal-containing waste treating agent of the present invention is usually in the form of powder, it can also be handled as a slurry liquid composition. That is, an aqueous solution containing a dispersant and water or an acid and an acid salt is added to the pozzolanic active substance,
If necessary, add a water-soluble polymer as a thickener, mix,
By kneading, the slurry of the present invention can be obtained.

The dispersant used in preparing this liquid composition plays a role in uniformly dispersing the pozzolanic active substance. As the dispersant, any water-soluble and capable of uniformly dispersing the pozzolanic active substance may be used.For example, for example, formalin condensate of naphthalene sulfonic acid, melamine sulfonic acid formalin condensate, cement such as lignin sulfonic acid condensate, cement concrete, etc. What is generally known as a dispersant can be used. These dispersants may be used in combination of two or more.

The amount of these dispersants varies depending on the type and particle size of the pozzolanic active substance used, but is usually 0.1 to 10 per 100 parts by weight of the total amount of the pozzolanic active substance.
Parts by weight, preferably 0.3 to 7 parts by weight, particularly preferably 0.5 to 5 parts by weight. If the amount of the dispersant is less than 0.1 part by weight, the dispersibility is undesirably deteriorated depending on the amount of water to be added. Even if it is used in an amount of 10 parts by weight or more, the effect corresponding to the added amount cannot be obtained, which is economically disadvantageous.

The amount of water used varies depending on the type and particle size of the pozzolanic active substance used, but is usually 10 to 60 parts by weight, preferably 15 to 40 parts by weight, and more preferably 100 parts by weight based on the total amount of the pozzolanic active substance. Preferably it is 18 to 30 parts by weight. If the amount is less than 10 parts by weight, it becomes difficult to obtain a liquid state, which is not preferable. If it is used in an amount of 60 parts by weight or more, dispersibility can be obtained, but undesirably, storage stability deteriorates. Generally, when the amount of the dispersant added is increased, the amount of water required for dispersion tends to be small.

When the treating agent of the present invention has a liquid composition, the treating agent of the present invention optionally contains a thickener. The thickener has the effect of improving the viscosity of the liquid composition and suppressing the sedimentation of the dispersed pozzolanic active substance powder particles (improving the storage stability). The thickener is not particularly limited as long as it is a water-soluble one. Poly (meth) acrylate, poly (meth) acrylamide, (meth) acrylic acid / (meth) acrylamide copolymer salt, methyl cellulose, hydroxy Ethyl cellulose, hydroxypropylcellulose, cellulose derivatives such as hydroxypropylmethylcellulose, polyethylene oxide, polypropylene oxide, polyvinylpyrrolidone, polyvinyl alcohol, specific examples of which can be used relatively high molecular weight such as xanthan gum, but are not limited thereto Not something. Further, two or more of these thickeners may be used in combination.

The molecular weight of the thickener used depends on the type of the thickener, the type and the particle size of the pozzolanic active substance used, and cannot be described uniformly, but the viscosity of the aqueous solution can be used as a guide for selection. . For example, the thickener 0.1.
For example, a 2% by weight aqueous solution has a viscosity of 50%.
Thickeners of at least cps are preferred, those of at least 100 cps are more preferred, and those of at least 150 cps are particularly preferred. The amount of the thickener used depends on the type of the thickener, the type and the particle size of the pozzolanic active substance to be used, and cannot be described uniformly, but is generally 0.01 to 100 parts by weight of the added water. To 5 parts by weight, preferably 0.02 to 3 parts by weight.

Since the heavy metal treating agent of the present invention contains a pozzolanic active substance as a main component, it does not have the drawback that it absorbs and solidifies during use or storage and becomes unusable as in the case of using cement. If the washing is not performed within a few hours, the solidified material will not adhere to the inner wall of the apparatus and the apparatus itself cannot be used. In addition, there is an advantage that the powdery composition can be handled as a liquid composition in the form of a slurry as described above when it is possible to handle the powdery work but dislikes the powder work. Another advantage that can be handled as a liquid composition is that it does not require large-scale facilities such as silos for storage because the volume is smaller than storing it as a powder, and it can be easily mixed and kneaded with heavy metal-containing waste. It has the advantage of becoming. As described above, the advantages of stabilizing heavy metals and workability are greater than when cement is used, and it is possible to use a liquid treatment agent if necessary, so a large facility such as a cement solidification facility is required. There is also a merit that does not.

In the embodiment of the present invention, it is preferable to use a sulfur-containing compound and a water-soluble phosphate in addition to the pozzolanic active substance. These can be used alone or, if necessary, appropriately selected from two or more kinds. Sulfur-containing compounds and water-soluble phosphoric acid chemically react with heavy metal ions in heavy-metal-containing waste in the presence of water to form heavy-metal sulfides, heavy-metal phosphates and chelate compounds that are hardly soluble in water, stabilizing heavy metals. It is said that the use of a pozzolanic active substance provides a stabilizing effect for heavy metals, which has not been obtained before.

The sulfur-containing compound that can be used is not particularly limited. Specific examples thereof include inorganic sulfur-containing compounds such as sodium sulfide, potassium sulfide, calcium sulfide and sodium hydrosulfide, and thiourea such as thiourea, ethylenethiourea and diphenylthiourea. Carbamic acid derivatives such as urea derivatives, dimethyldithiocarbamic acid, diethyldithiocarbamic acid and salts thereof, organic sulfur-containing compounds such as thiomalic acid, 2-benzothiazole thiol, thiocyanuric acid and salts thereof, and substituted polyethyleneimine dithiocarboxylates Examples thereof include a sulfur-containing polymer compound, and a thiourea derivative or a thiocarbamic acid derivative is preferable. Two or more of these sulfur-containing compounds may be used in combination.

The amount of the sulfur-containing compound to be used must be appropriately determined according to the type of pozzolanic active substance, particle size and specific surface area, or the type of heavy metal-containing waste, particularly the amount of heavy metal ions eluted.
1 to 100 parts by weight, preferably 2 to 5 parts by weight per 0 parts by weight
0 parts by weight, particularly preferably 2.5 to 25 parts by weight.

Specific examples of the water-soluble phosphate that can be used include:
Ammonium salts such as diammonium hydrogen phosphate, ammonium dihydrogen phosphate and triammonium phosphate; alkali metal salts such as monopotassium phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, disodium hydrogen phosphate and sodium dihydrogen phosphate; primary phosphoric acid Calcium, alkaline earth metal salts such as dibasic calcium phosphate, potassium metaphosphate, sodium metaphosphate, sodium tripolyphosphate, sodium polyphosphate, lime superphosphate and the like can be mentioned, and lime superphosphate or sodium tripolyphosphate is particularly preferred. Two or more of them may be used in combination. The amount of the water-soluble phosphate used must be appropriately determined according to the type of pozzolanic active substance, the particle size and specific surface area, or the type of heavy metal-containing waste, particularly the amount of heavy metal ion eluted.
1 to 100 parts by weight, preferably 2 to 100 parts by weight
It is 50 parts by weight, particularly preferably 2.5 to 25 parts by weight.

These sulfur-containing compounds and water-soluble phosphates can be used as a treating agent of the present invention by mixing them with a pozzolanic active substance in a solid state. It can also be used as a treating agent of the present invention.

When the heavy metal-containing waste is municipal garbage incineration fly ash or the like in which the eluate used in the dissolution test of the Announcement No. 13 is highly alkaline, amphoteric heavy metal compounds such as lead compounds are easily dissolved, so that hydrochloric acid and sulfuric acid are used. , Nitric acid, poly aluminum chloride,
Addition of an acidic substance such as an inorganic acidic substance such as ferrous chloride or aluminum sulfate, or an organic acidic substance such as acetic acid or citric acid to control the pH to be weakly alkaline enhances the heavy metal stabilizing effect of the treating agent of the present invention. . In addition, when the eluate in the dissolution test of Announcement No. 13 is a waste containing heavy metals such as electric furnace ash, melt fly ash, and contaminated soil that is neutral or acidic, the treating agent of the present invention may be treated with sodium hydroxide, hydroxide or the like. Hydroxides of alkali metals such as potassium, carbonates of alkali metals such as sodium carbonate and potassium carbonate, hydroxides of alkaline earth metals such as calcium hydroxide, magnesium hydroxide and barium hydroxide, sodium silicate and potassium silicate PH is weakly alkaline by adding basic substances such as alkali metal silicates such as sodium metasilicate and sodium orthosilicate, alkali metal phosphates such as monosodium phosphate and disodium phosphate, cement, cement clinker, etc. Control enhances the effect of stabilizing heavy metals of the treating agent of the present invention. However, when the treating agent of the present invention is used for the purpose of stabilizing and solidifying (strengthening) the heavy metal-containing waste, it is preferable to add a compound that promotes the pozzolanic reaction such as calcium hydroxide.

The amount of the acidic substance or the basic substance to be used is preferably such that the pH of the eluate after the dissolution test described in Announcement 13 can be adjusted to 8 to 12. The basic substance or the acidic substance may be added in advance to the treating agent of the present invention, but may be used in the stabilizing treatment method of the present invention described later.

Further, in the treating agent of the present invention, various admixtures may be used as necessary for the purpose of improving the formability of the treated heavy metal-containing waste. Specific examples of the admixture that can be used include pulverized slow-cooled slag, ferrochrome slag, silica, alumina, talc, silica sand, silica powder, clay, kaolin, calcium carbonate, crushed ceramics, titania, zirconia, and river sand. Filler, glass fiber,
Fibers such as carbon fiber, vinylon fiber, nylon fiber, aramid fiber, polypropylene fiber, acrylic fiber, and polyester fiber, and fibers such as cellulose fiber, steel fiber, and alumina fiber are exemplified. Further, a curing retarder such as sugar and glucose, a surface treating agent such as a silane coupling agent, a pigment, and the like may be used as necessary.

The treating agent of the present invention containing components other than the pozzolanic active substance can be obtained by uniformly mixing the above components at a predetermined ratio. When the powdery treatment agent of the present invention is obtained, the respective components may be powder-mixed by a known mixing method.
The method of mixing when obtaining the liquid treatment agent of the present invention is not particularly limited, but a predetermined amount of a dispersant, water, and, if necessary, a thickener used are mixed to form an aqueous solution. The method of adding to the mixed powder component such as the pozzolanic active substance is preferable because the whole becomes easily uniform.

The method for stabilizing heavy metal-containing wastes of the present invention (hereinafter referred to as the processing method of the present invention) comprises a treating agent of the present invention,
Mix and knead the heavy metal-containing waste and, if necessary, water.
Water is added when the heavy metal-containing waste does not contain water, or when it is contained but insufficient for mixing and kneading. The amount of water used depends on the water content of the heavy metal-containing waste and its particle size.
5 to 80 parts by weight with respect to 0 parts by weight (calculated in a dry state),
Preferably it is 10 to 50 parts by weight. However, this amount differs depending on the shape of the treated body after the stabilization treatment is performed, that is, whether it is pelletized, granulated, or muddy. . The time required for the treatment (mixing, kneading time) is not particularly limited,
It is only necessary that the waste and the treating agent can be uniformly kneaded. The equipment for mixing and kneading them and the order of adding them are not particularly limited. That is, the processing agent of the present invention and water as an optional component may be added and mixed or kneaded before waste is generated, or may be mixed or kneaded after being generated as waste. Furthermore, the treatment agent of the present invention mixed in advance may be mixed with the heavy metal-containing waste, or each component constituting the treatment agent of the present invention may be mixed with the heavy metal-containing waste. The mixing method can be, for example, a kneader-ruder type or an Erich-type mixing kneader equipped with a stirrer when performing a batch process. For example, a mixing method using a kinetic method, a single-shaft or twin-shaft paddle-type kneader, a pan-type mixer, a vibro mixer, or the like can be used.

In the treatment method of the present invention, when the treating agent of the present invention, the heavy metal-containing waste and water as an optional component are mixed, kneaded, or after mixing and kneading, heat treatment of the kneaded material suppresses heavy metal elution. This is preferable because the effect is significantly improved and the time required for stabilization can be reduced. In the heat treatment, heat generated during kneading may be used, or the kneaded material may be heated as it is or after kneading. Heating temperature is 40 ° C or higher, preferably 50 ° C
That is all. The heating method may be a known method such as a mechanical method or a physicochemical method as described above. The heating time is
Although it depends on the thermal conductivity of the kneaded material, it is usually 5 minutes or more, preferably 10 minutes or more, and it is sufficient to perform the treatment for up to 24 hours from the viewpoint of uniformity of the processed material and workability.

The waste which can stabilize heavy metal ions by the treatment agent and treatment method of the present invention is not particularly limited.
Industrial wastes including municipal incineration ash and fly ash, contaminated soil, sludge, or metals that must satisfy the criteria set forth in Prime Ministerial Decree No. 5 can be treated alone or in combination. When stabilizing municipal garbage incineration fly ash by the treatment method of the present invention, if the treatment agent of the present invention is added to the flue together with slaked lime and activated carbon, the heat of the flue is utilized simultaneously with the treatment of exhaust gas such as HCl and dioxin. This is advantageous because the stabilized heavy metal can be treated.

According to the treatment agent and the treatment method of the present invention, heavy metals in heavy metal-containing waste are stabilized, and heavy metals are hardly eluted from the kneaded material after treatment. In the metal elution test by the test method for hazardous substances contained in industrial waste, the elution amount of heavy metal ions is below the regulation value.

The thus obtained treated product of the present invention may be used as it is or, if necessary, crushed to be used as an aggregate for cement / concrete or an aggregate for road pavement. It can be used as civil engineering and construction materials by molding into a shape.

[0035]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 7 Incineration fly ash (lead content: 2600) obtained from an incineration plant for municipal waste
mg / kg) (hereinafter referred to as "A fly ash") 100 parts by weight and a pozzolanic active substance of the type shown in Table 1 were added and mixed, and a predetermined amount of water was added and kneaded. A lead dissolution test was performed based on the above. Table 2 shows the results. still,
The amounts of pozzolanic active substance and water used in each example are also shown in Table 2. The Pb elution test result of the fly ash used was 2
It was 1.2 ppm.

[0037]

Table 1 Pozzolanic activity Average particle size SiO ₂ Al ₂ O ₃ Specific surface area Type of substance (μm) Content (wt%) Content (wt%) (cm ² / g) Example 1 Silica dust 1 90 1.5 200,000 Example 2 White Carbon 5 930 2,000,000 Example 3 Aerosil 7 × 10 ⁻³ 99.9 0 3,800,000 Example 4 Metakaolin 0.4 50 38 30,000 Example 5 Diatomaceous Earth 10 89.2 5 150,000 Implementation Example 6 Talc 10 62.5 0.2 40,000 Example 7 Activated clay 5 79.5 10 2,500,000

[0038]

Table 2 Table 2 Pozzolanic active substance Water addition amount Annealing No. 13 lead elution amount Addition amount (parts by weight) (parts by weight) (ppm) 1 day after 1 week after 4 weeks after 13 weeks Example 18 35 0.27 0.10 0.03 ND Example 2 5 35 0.25 0.10 ND ND Example 3 3 35 0.15 ND ND ND Example 4 5 35 0.20 0.04 ND ND Example 5 9 35 0.28 0.15 0.03 ND Example 6 9 35 0.28 0.18 0.07 ND Example 535 0.23 0.08 ND ND In Table 2, ND is below the detection limit (the same applies hereinafter).

Examples 8 to 18 100 parts by weight of fly ash A, 3 parts by weight of Aerosil whose average particle diameter and specific surface area were changed as shown in Table 3, 35 parts by weight of water were added and kneaded. The treatment was performed under the treatment conditions shown in Table 3, and a lead elution test based on the notification of the Environment Agency No. 13 was performed. The results are shown in Table 3.

[0040]

Table 3 Average particle size Specific surface area Treatment conditions Announcement No. 13 (nm) (cm ² / g) Temperature Time Lead elution amount (ppm) Example 8 16 1,300,000 40 ° C 18 hours 0.20 Example 9 12 2,000,000 55 ° C 12 hours 0.12 Example 10 7 3,000,000 70 ° C 6 hours ND Example 11 7 3,800,000 80 ° C 4 hours ND Example 12 16 1,300,000 90 ° C 2 hours ND Example 13 12 2,000,000 80 ° C 4 hours ND Example 147 3,000,000 Room temperature 24 hours 0.22 Example 15 7 3,800,000 40 ° C 18 hours 0.19 Example 16 16 1,300,000 Room temperature 24 hours 0.28 Example 17 12 2,000,000 Room temperature 24 hours 0.25 Example 18 7 3,800,000 70 ° C 3 hours ND

Examples 19 to 26 Incinerated fly ash (lead content: 3500) obtained from an incineration plant for municipal waste
mg / kg), 100 parts by weight of silica dust (SiO ₂ content 90 wt%, average particle size 0.1 μm, specific surface area 200,0
00 cm ² / g) and thiourea were mixed with the treating agent of the present invention prepared by mixing the amounts shown in Table 4, water was added in the amount shown in Table 4, and the mixture was kneaded. A lead dissolution test was performed based on the above. The results are shown in Table 4. The Pb elution test result of the used fly ash was 299 ppm.

[0042]

Table 4 Silica dust Addition of thiourea Water addition amount Announcement No. 13 Addition amount (parts by weight) Amount (parts by weight) (parts by weight) Lead elution amount (ppm) Example 19 44 32 0.05 Example 20 5 3 32 0.09 Example 21 6 232 0.12 Example 22 5 232 0.15 Example 23 4 3 32 0.14 Example 24 3 3 32 0.15 Example 25 3 232 0 .25 Example 26 2.5 2.5 32 0.20

Examples 27 to 36 Incineration fly ash (lead content: 1700) obtained from an incineration plant for municipal waste
mg / kg), 100 parts by weight of metakaolin (SiO ₂ content: 50 wt%, average particle size: 0.4 μm, specific surface area: 30,000)
0 cm ² / g) 3 parts by weight of the treating agent of the present invention prepared by mixing 2 parts by weight of each of the water-soluble sulfide, water-soluble phosphate and water-soluble acidic substance shown in Table 5 were mixed with water. Was added in the amount shown in Table 5 and kneaded, and then a lead elution test based on Notification No. 13 of the Environment Agency was conducted. The results are shown in Table 5. The Pb elution test result of the used fly ash was 6.85 p.
pm.

[0044]

Table 5 Amount of water added to additives Announcement No. 13 Type (parts by weight) Lead elution amount (ppm) Example 27 Calcium sulfide 32 0.13 Example 28 Soda hydrosulfide 32 0.11 Example 29 Sulfurization Soda 32 0.15 Example 30 Diphenylthiourea 32 0.02 Example 31 Dimethyldithio 32 ND Sodium carbamate Example 32 Lime superphosphate 32 0.08 Example 33 Disodium hydrogen phosphate 32 0.17 Example 34 Tripoly Sodium phosphate 32 0.06 Example 35 Aluminum sulfate 32 0.11 Example 36 Polyaluminum chloride 32 0.22 Example 37 Ferrous sulfate 32 0.17

Examples 38 to 42 100 parts by weight of heavy metal-containing waste shown in Table 6, white carbon (SiO ₂ content: 93 wt%, average particle size: 5 μm,
Specific surface area 2,000,000 cm ² / g) 5 parts by weight and Table 6
After adding the treatment agent of the present invention mixed with the amount of white carbon and / or slaked lime shown in Table 2 and water in the amount shown in Table 6, and kneading the mixture, a lead elution test based on Notification No. 13 of the Environment Agency was conducted. The results are shown in Table 6.

[0046]

Table 6 Waste Waste White slaked lime water Waste type No. 13 Lead elution amount Carbon addition amount Addition amount Lead elution amount Addition amount (ppm) (parts by weight) (parts by weight) (parts by weight) (ppm) Example 38 Fly ash 2.554 5 128 0.06 Example 39 Incinerated ash 0.70 310 0.04 Example 40 Incinerated ash 1.85 30.5 25 ND Example 41 Sludge 12.3 5 1 10 0.21 Example 42 Concentrated Waste Liquid 8.85 5 10 0.15

Examples 43 to 46 Silica dust (SiO ₂ content: 90% by weight, average particle size: 0.3 wt.
1 μm, specific surface area of 200,000 cm ² / g), 2 parts by weight of sodium salt of copolymer of acrylic acid and maleic anhydride (average molecular weight: 45,000), 20 parts by weight of water, and average molecular weight of 3,000,000 Was added and mixed to obtain a liquid heavy metal-containing waste treating agent of the present invention. The viscosity of this treatment agent after preparation is 3,
It was 500 cps (B-type viscometer). One week or one month after standing in a container, pseudo-coagulation occurred. However, when vibration was applied, the liquid recovered to a liquid state, and the viscosity was measured to be 3,300 cps and 3,450 cps, respectively.
In addition, after preparation, even if constantly stirred in a container,
In addition, the liquid after preparation was maintained for one month or more by stirring intermittently every two to three days.

After one week from the preparation, the liquid treating agent for heavy metal-containing waste of the present invention and water were kneaded with A fly ash in the amounts shown in Table 7, respectively, and then kneaded with the Environment Agency Notification No. 13. A lead dissolution test was performed. The results are shown in Table 7.

[0049]

Table 7 Table 7 Treatment agent Addition amount of Announcement No. 13 Addition amount of water Lead elution amount (ppm) (parts by weight) (parts by weight) 1 day after 1 week after 13 weeks Example 43 3 34 0.30 0.10 0.02 Example 44 5 33 0.25 0.03 ND Example 45 7 32 0.18 ND ND Example 46 9 31 0.10 ND ND

[0050]

The treatment agent for heavy metal-containing wastes of the present invention comprises:
It is suitable for stabilizing heavy metal-containing waste, and can stabilize the elution of heavy metal ions to a high degree, and its effect is continuous. In addition, since it can be stored in a liquid composition, it is an unprecedented heavy metal treating agent that has the advantages of each of the conventional solidification of cement and the disadvantage of chemical treatment. Further, the treatment method of the present invention can easily stabilize a heavy metal-containing compound without using a special apparatus. Furthermore, the treated product obtained by the present treatment method can impart strength equal to or higher than the solidification of cement, and can be recycled as civil engineering and building materials such as aggregates and pavement materials.

Claims (15)

[Claims] An agent for treating heavy metal-containing waste, comprising a pozzolanic active substance which is solid at normal temperature. 2. The treating agent according to claim 1, wherein the content of the silica component in the pozzolanic active substance in terms of SiO ₂ is at least 40% by weight. 3. An alumina component in the pozzolanic active material is Al ₂ O
2. The treating agent according to claim 1, wherein the alumina component content in terms of ₃ is 0.2% by weight or more and less than 40% by weight. 4. The treating agent according to claim 1, wherein the average particle size of the pozzolanic active substance is 30 μm or less. 5. The specific surface area of the pozzolanic active substance is 5,000.
Treatment agent according to any one of claims 1 to 4 is ~3,000,000cm ² / g. 6. The method according to claim 1, further comprising a dispersant and water.
The treatment agent according to any one of the above. 7. The treating agent according to claim 1, further comprising one or more sulfur-containing compounds and / or water-soluble phosphates. 8. The treating agent according to claim 7, wherein the sulfur-containing compound is a thiourea derivative and / or a carbamic acid derivative. 9. The treating agent according to claim 7, wherein the water-soluble phosphate contains one or more of lime superphosphate and / or sodium tripolyphosphate. 10. A heavy metal-containing waste, characterized in that the treatment agent according to any one of claims 1 to 9 and, if necessary, water are added, followed by mixing and kneading. Processing method. 11. A waste material containing a heavy metal, the treatment agent according to any one of claims 1 to 9, and water as required, followed by mixing and kneading, followed by heat treatment at 40 ° C. or more. Of heavy metal-containing waste. 12. The method according to claim 1, wherein the heavy metal-containing waste is incineration ash or fly ash from a garbage incineration plant, contaminated soil, or industrial waste containing metals that must satisfy the criteria set forth in Prime Ministerial Ordinance No. 5. Item 13. The method for treating heavy metal-containing waste according to Item 10 or 11. 13. A treatment agent and a base according to claim 1, wherein the pH of the eluate after the dissolution test based on the notification of the Environment Agency No. 13 is neutral or acidic, and the waste is a heavy metal-containing waste. The treatment method according to any one of claims 10 to 12, wherein the treatment is carried out by adding a toxic substance. 14. The treatment agent and the acidic substance according to any one of claims 1 to 9, wherein the pH of the eluate after the elution test based on the notification of the Environment Agency No. 13 is basic, and the waste is a heavy metal-containing waste. The treatment method according to any one of claims 10 to 12, wherein the treatment is carried out by adding. 15. A processed product obtained by the processing method according to any one of claims 10 to 14.